Method for fabricating coa array substrate, array substrate and display device

ABSTRACT

A method for fabricating a COA array substrate, an array substrate and a display device are provided. The COA array substrate includes a photoresist layer disposed on a protection layer, wherein a color filter receiving hole is formed in the photoresist layer, and a color filter layer is formed in the color filter receiving hole, an entire surface of the photoresist layer is flushed with an entire surface of the color filter layer such that the photoresist layer functions as the planarized layer.

This application is a divisional of U.S. application Ser. No. 14/351,639filed on Apr. 14, 2014 and Applicant claims priority under 35 U.S.C. §120 of U.S. application Ser. No. 14/351,639, which application is anational stage application under 35 U.S.C. § 371 of PCT Application No.PCT/CN2013/077492 filed Jun. 19, 2013 which claims priority under 35U.S.C. § 119 from Chinese Patent Application No. 201310108090.1 filedMar. 29, 2013, the disclosures of each of which are hereby incorporatedby reference. A certified copy of priority Chinese Patent ApplicationNo. 201310108090.1 is contained in parent U.S. application Ser. No.14/351,639. The International Application under PCT article 21(2) wasnot published in English.

FIELD OF THE ART

Embodiments of the invention relate to the field of liquid crystaldisplay technologies, more particularly, to a method for fabricating acolor filter on array (COA) array substrate, an array substrate and adisplay device.

BACKGROUND

COA array substrate refers to a TFT substrate 11 above which a colorfilter layer 13 is fabricated, wherein the TFT substrate 11 comprises asubstrate 111 and a Thin Film Transistor (TFT) 112. With such a design,it can reduce the width of the black matrix while improving the apertureratio of the display region. FIG. 1 illustrates a configuration of aconventional COA array substrate and FIG. 2 illustrates an exposingprocedure for forming a via hole 15.

Currently, methods for fabricating the color filter layer on the TFTsubstrate mainly involve patterning process or ink-jet printing process.A separately fabricated barricade structure is required for theconventional ink-jet printing process, which is then removed afterfinishing fabricating the color filter layer 13 (the color filter layeris formed by coating a protection layer 12 on the TFT substrate and thenperforming a patterning process). Thereafter a planarized layer 14 isformed, thereby forming the COA array substrate structure. Meanwhile, aseparate patterning process is required to form the via hole 15.Therefore, the process is complicated and the production efficiency islow while the cost is high.

SUMMARY

Embodiments of the invention provide a method for fabricating an arraysubstrate, an array substrate and a display device which can reduce thefabrication processes and the cost while improving the productionefficiency.

A first aspect of the invention provides a method for fabricating a COAarray substrate, the COA array substrate comprises a TFT substrate and acolor filter layer disposed on the TFT substrate, the method comprisesthe following steps: forming a protection layer on the TFT substrate;coating a photoresist layer on the protection layer, the photoresistlayer functions as a planarized layer, wherein the TFT substratecomprises a substrate and a TFT; forming a color filter receiving holein the photoresist layer through a photolithography process; fabricatingthe color filter layer in the color filter receiving hole.

The photoresist layer in the invention has a good fluidity, thereforethe step different is very small. As a result, the photoresist layer mayfunction as the planarized layer at the same time. A pattern comprisingthe color filter receiving hole is formed by exposing and developing thephotoresist layer through a patterning process. In comparison withconventional method for fabricating an array substrate, the planarizedlayer is no longer formed separately, making the manufacturing stepsimple while saving production cost.

A second aspect of the invention provides a COA array substrate,comprising a photoresist layer 21 disposed on a protection layer 12, thephotoresist layer 21 functions a planarized layer, a color filterreceiving hole 32 is formed in the photoresist layer, and a color filterlayer 13 is formed in the color filter receiving hole 32.

As the photoresist layer of the array substrate according to theinvention not only has the color filter receiving hole formed thereinbut also functions as the planarized layer, the cost of the arraysubstrate is low.

A third aspect of the invention provides a display device comprising theabove COA array substrate.

The display device is of low cost and simple manufacturing steps as itis provided with the above array substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to clearly illustrate the technical solution of the embodimentsof the invention, the drawings of the embodiments will be brieflydescribed in the following; it is obvious that the described drawingsare only related to some embodiments of the invention and thus are notlimitative of the invention.

FIG. 1 schematically illustrates a configuration of a conventional COAarray substrate;

FIG. 2 schematically illustrates a diagram of exposing a photoresistlayer of a COA array substrate in a method for fabricating an arraysubstrate in accordance with Embodiment 1 of the invention;

FIG. 3 schematically illustrates a diagram after exposing thephotoresist layer of the COA array substrate in the method forfabricating the COA array substrate in accordance with Embodiment 1 ofthe invention;

FIG. 4 schematically illustrates a diagram of fabricating a color filterlayer of the COA array substrate in the method for fabricating the COAarray substrate in accordance with Embodiment 1 of the invention;

FIG. 5 schematically illustrates a diagram of fabricating a via holeabove the COA array substrate in the method for fabricating the COAarray substrate in accordance with Embodiment 1 of the invention; and

FIG. 6 schematically illustrates a diagram of fabricating a pixelelectrode or an anode in the via hole of the COA array substrate in themethod for fabricating the COA array substrate in accordance withembodiments of the invention.

DETAILED DESCRIPTION

In order to make objects, technical details and advantages of theembodiments of the invention apparent, the technical solutions of theembodiment will be described in a clearly and fully understandable wayin connection with the drawings related to the embodiments of theinvention. It is obvious that the described embodiments are just a partbut not all of the embodiments of the invention. Based on the describedembodiments herein, those skilled in the art can obtain otherembodiment(s), without any inventive work, which should be within thescope of the invention.

Embodiment 1

With reference to FIGS. 3 to 6, the embodiment of the invention providesa method for fabricating a COA array substrate, comprising:

Step 1: first forming components such as a TFT 112 and metal wires on asubstrate 111 to finish fabricating a TFT substrate 11; forming aprotection layer 12 on the TFT substrate 11, wherein the protectionlayer 12 is configured for protecting the substrate.

Step 2: coating a photoresist layer 21 on the protection layer 12,exposing the photoresist layer 21 with a mask 22 through a patterningprocess, the exposed region is a color pixel region; developing thecolor pixel region after exposing; then baking to form a color filterreceiving hole 32; the photoresist layer 21 also functions as aplanarized layer 14.

Step 3: adding dyestuff into the color filter receiving hole 32 to forma color filter layer 13. Herein, as the step difference of thephotoresist layer 21 is very small, the photoresist layer 21 may alsofunction as the planarized layer 14. Therefore there is no need tofabricate the planarized layer 14, making the fabrication processsimple, production efficiency high and cost low.

Preferably, forming the color filter layer in the color filter receivinghole 32 comprises: forming the color filter layer 13 in the color filterreceiving hole 32 by ink-jet printing process. In the method provided bythe embodiment, the photoresist layer 21 is exposed and developed duringthe patterning process to form the color filter receiving hole 32. As apositive photoresist is used to fabricate the color filter receivinghole 32, the photoresist will still exist in other regions after thedeveloping (in the case of using a negative photoresist, the regionhaving the color filter receiving hole 32 is not irradiated while otherregions are irradiated, therefore the photoresist still exist in otherregions after the developing). The remaining photoresist layer 21actually forms a barricade. In this case, there is no need forseparately forming the barricade when using ink-jet printing process toform the color filter layer 13. In comparison with conventionalfabrication method, the step of forming the barricade is omitted, whichcan significantly improve the production efficiency and reduce theproduction cost.

Preferably, the COA array substrate is an OLED array substrate, and step2 comprises:

with reference to FIG. 3, forming the color filter receiving hole 32 anda first via hole 31 through a single patterning process, wherein thefirst via hole 31 penetrates through the planarized layer 14;

with reference to FIG. 5, etching the protection layer 12 in the firstvia hole 31 region to form a via hole 15 exposing a drain electrode ofthe TFT 112.

After forming the color filter layer 13 at step 3, the method furthercomprises: forming an OLED anode on the color filter layer 13, the OLEDanode 16 is electrically connected to the drain electrode of the TFT 112through the via hole 15, as illustrated in FIG. 6.

The OLED anode may also be formed on the TFT substrate 11, the OLEDanode may be directly connected to the drain electrode of the TFT 112;in this case there is no need to form the via hole 15 through thepatterning process.

Preferably, the COA array substrate is a TFT-LCD array substrate, andstep 2 comprises:

with reference to FIG. 3, forming the color filter receiving hole 32 anda first via hole 31 through a single patterning process, the first viahole 31 penetrates through the planarized layer 14;

with reference to FIG. 5, etching the protection layer 12 in the firstvia hole 31 region to form a via hole 15 exposing a drain electrode ofthe TFT 112;

After forming the color filter layer 13 at step 3, the method furthercomprises: forming a pixel electrode 17 on the color filter layer 13,the pixel electrode is connected to a drain electrode of the TFT 112through the via hole 15, as illustrated in FIG. 6.

The pixel electrode may also be formed on the TFT substrate 11, thepixel electrode may be directly connected to the drain electrode of theTFT 112; in this case there is no need to form the via hole 15 throughthe patterning process.

Embodiment 2

The embodiment provides an array substrate, comprising a photoresistlayer 21 disposed on a protection layer 12, wherein the photoresistlayer 21 functions as a planarized layer 14, a color filter receivinghole 32 is formed in the photoresist layer 21, a color filter layer 13is formed in the color filter receiving hole 32. As the photoresistlayer 21 functions as the planarized layer 14, the cost can be savedduring fabrication.

Preferably, the array substrate is an OLED array substrate, a via hole15 penetrating through the photoresist layer 14 and the protection layer12 is disposed on the COA array substrate, an OLED anode is electricallyconnected to a drain electrode of a TFT 112 on the OLED substratethrough the via hole 15. It can be contemplated that the OLED may alsobe formed on the TFT substrate 11, the OLED anode is directly connectedto the drain electrode of the TFT 112; in this case there is no need toform the via hole 15.

Preferably, the array substrate is a TFT-LCD array substrate, a via hole15 penetrating through the photoresist layer 14 and the protection layer12 is disposed on the COA array substrate, a pixel electrode iselectrically connected to a drain electrode of a TFT 112 on the TFT-LCDarray substrate through the via hole 15. It can be contemplated that thepixel electrode may also be formed on the TFT substrate 11, the pixelelectrode may be directly connected to the drain electrode of the TFT112; in this case there is no need to form the via hole 15.

The COA array substrate of the embodiment may be fabricated by using thefabrication method of Embodiment 1 without the need for the planarizedlayer 14 and the barricade. Detailed description will not be provided.The array substrate thus has high production efficiency and a low cost.

Embodiment 3

The embodiment provides a display device comprising the above arraysubstrate. It may also comprise conventional structures of the displaydevice such as a frame.

An example of the display device is a liquid crystal display (LCD)device, wherein an array substrate and an opposed substrate are disposedopposed to each other to form a liquid crystal cell, a liquid crystalmaterial is filled in the liquid crystal cell. The opposed substrate isfor example a color filter substrate. A pixel electrode of each pixelunit of the array substrate is adapted to applying an electric field tocontrol the rotation of the liquid crystal material, thereby displayingimages. In some examples, the LCD device further comprises a backlightmodule for providing backlight to the array substrate.

Another example of the display device is an organic electroluminescentdisplay (OLED) device, wherein an organic light emitting layer is formedon the array substrate, a pixel electrode of the pixel unit functions ananode or a cathode for driving the organic light emitting layer todisplay images.

As the display device comprises the array substrate, the fabricationprocess is simple and the cost is low.

What are described above is related to the illustrative embodiments ofthe disclosure only and not limitative to the scope of the disclosure;the scopes of the disclosure are defined by the accompanying claims.

What is claimed is:
 1. A COA array substrate, comprising a photoresistlayer disposed on a protection layer, wherein a color filter receivinghole is formed in the photoresist layer, and a color filter layer isformed in the color filter receiving hole, an entire surface of thephotoresist layer is flushed with an entire surface of the color filterlayer such that the photoresist layer functions as the planarized layer.2. The COA array substrate of claim 1, wherein the COA array substrateis an OLED array substrate, a via hole penetrating through thephotoresist layer and the protection layer is disposed on the COA arraysubstrate, an OLED anode is electrically connected to a drain electrodeof a TFT on the OLED substrate through the via hole.
 3. The COA arraysubstrate of claim 1, wherein the COA array substrate is a TFT-LCD arraysubstrate, a via hole penetrating through the photoresist layer and theprotection layer is disposed on the COA array substrate, a pixelelectrode is electrically connected to a drain electrode of a TFT on theTFT-LCD substrate through the via hole.
 4. A display device comprisingthe COA array substrate of claim 1.